The present invention relates to a transmission brake disengagement apparatus for mounting on a drag race car and more particularly, to a method of activating and deactivating a transmission brake of a drag race car and a transmission brake disengagement apparatus having a mechanical actuation switch for providing an electrical signal to effect the disengagement of an electrically actuated transmission brake of a drag race car.
In the sport of drag racing, drivers strive to cover a fixed distance in a preselected time and the difference between winning and losing a race is often measured in thousandth's of a second. Accordingly, the nature of a drag race places importance on the consistency of operation of the mechanisms of the car and the consistency of the reaction time of the driver with the result that getting off to a good start being a matter of great importance to race car drivers.
In one form of drag racing, cars may cross the starting line only after the green light or starting light comes on. If the car crosses the starting line prior to the green light, the driver is said to have “red lighted” and automatically loses. Conventional drag race cars are equipped with a transmission brake which comprises a solenoid which when energized holds the car at the starting line thereby allowing the driver to power-up the engine of the car prior to the start of the race and to maintain the engine at or near maximum power until the solenoid is de-energized.
Typically, the start of a drag race is first initiated by a series of yellow lights which are illuminated in sequence with each light being illuminated for five-tenths of a second before the green light appears. Thus, the driver of a drag race car is in a position to judge the time the green light will illuminate and react by releasing a mechanical starting switch which the driver has been holding down by use of continuous hand pressure to electronically disengage the transmission brake. Upon disengagement of the transmission brake, the car will accelerate down the track.
In order to improve starting consistency a delay box having a timing circuit was developed that operated to disengage the transmission brake of the car and eliminate the need to estimate the time the green light will illuminate. The circuit included a programmable down counter and a clock which begins a timing sequence when a starting switch is released. Thus, the driver could release pressure on the starting switch when the first of a series of yellow lights illuminate and the transmission brake would be disengaged when the counter reached a zero count. Since the driver could allow for his reaction time in setting the counter, the introduction of this circuit theoretically placed him in a position to attain an ideal start.
Unfortunately, a driver's reaction time between races is not consistent. Further, the position of the diver's hand, the hand strength of the driver, the temperature and the amount of use of the mechanical starting switch can all effect the activation time of the starting switch and the consistency of the timing of the start. Further, the driver may overestimate or underestimate his reaction time thereby resulting in his car starting prior to or after the green light is illuminated.
Accordingly, a need exist for a transmission brake disengagement apparatus for improving the consistency of activating the timing circuit of a delay box for disengaging the transmission brake of a drag race car which is not adversely effected by the position or strength of the driver's hand or the temperature and the amount of use of the apparatus.